# wrap VipsImage

from __future__ import division

import numbers

import pyvips
from pyvips import ffi, glib_lib, vips_lib, Error, _to_bytes, \
    _to_string, GValue, at_least_libvips

ffi.cdef('''
    typedef struct _VipsImage {
        VipsObject parent_instance;

        // opaque
    } VipsImage;

    const char* vips_foreign_find_load (const char* name);
    const char* vips_foreign_find_load_buffer (const void* data, size_t size);
    const char* vips_foreign_find_save (const char* name);
    const char* vips_foreign_find_save_buffer (const char* suffix);

    VipsImage* vips_image_new_matrix_from_array (int width, int height,
            const double* array, int size);
    VipsImage* vips_image_new_from_memory (const void* data, size_t size,
            int width, int height, int bands, int format);

    VipsImage* vips_image_copy_memory (VipsImage* image);

    GType vips_image_get_typeof (const VipsImage* image,
        const char* name);
    int vips_image_get (const VipsImage* image,
        const char* name, GValue* value_copy);
    void vips_image_set (VipsImage* image, const char* name, GValue* value);
    int vips_image_remove (VipsImage* image, const char* name);
    char** vips_image_get_fields (VipsImage* image);

    char* vips_filename_get_filename (const char* vips_filename);
    char* vips_filename_get_options (const char* vips_filename);

    VipsImage* vips_image_new_temp_file (const char* format);

    int vips_image_write (VipsImage* image, VipsImage* out);
    void* vips_image_write_to_memory (VipsImage* in, size_t* size_out);


''')


# either a single number, or a table of numbers
def _is_pixel(value):
    return (isinstance(value, numbers.Number) or
            (isinstance(value, list) and not
            isinstance(value, pyvips.Image)))


# test for rectangular array of something
def _is_2D(array):
    if not isinstance(array, list):
        return False

    for x in array:
        if not isinstance(x, list):
            return False
        if len(x) != len(array[0]):
            return False

    return True


# apply a function to a thing, or map over a list
# we often need to do something like (1.0 / other) and need to work for lists
# as well as scalars
def _smap(func, x):
    if isinstance(x, list):
        return list(map(func, x))
    else:
        return func(x)


def _call_enum(image, other, base, operation):
    if _is_pixel(other):
        return pyvips.Operation.call(base + '_const', image, operation, other)
    else:
        return pyvips.Operation.call(base, image, other, operation)


def _run_cmplx(fn, image):
    """Run a complex function on a non-complex image.

    The image needs to be complex, or have an even number of bands. The input
    can be int, the output is always float or double.
    """
    original_format = image.format

    if image.format != 'complex' and image.format != 'dpcomplex':
        if image.bands % 2 != 0:
            raise Error('not an even number of bands')

        if image.format != 'float' and image.format != 'double':
            image = image.cast('float')

        if image.format == 'double':
            new_format = 'dpcomplex'
        else:
            new_format = 'complex'

        image = image.copy(format=new_format, bands=image.bands / 2)

    image = fn(image)

    if original_format != 'complex' and original_format != 'dpcomplex':
        if image.format == 'dpcomplex':
            new_format = 'double'
        else:
            new_format = 'float'

        image = image.copy(format=new_format, bands=image.bands * 2)

    return image


# https://stackoverflow.com/a/22409540/1480019
def _with_metaclass(mcls):
    def decorator(cls):
        body = vars(cls).copy()
        # clean out class body
        body.pop('__dict__', None)
        body.pop('__weakref__', None)

        return mcls(cls.__name__, cls.__bases__, body)

    return decorator


# decorator to set docstring
def _add_doc(name):
    try:
        docstring = pyvips.Operation.generate_docstring(name)
    except Error:
        docstring = None

    def _doc(func):
        func.__doc__ = docstring
        return func

    return _doc


# decorator to set deprecated
def _deprecated(note):
    def _dep(func):
        func.__deprecated__ = note
        return func

    return _dep


# metaclass for Image ... getattr on this implements the class methods
class ImageType(type):
    def __getattr__(cls, name):
        # logger.debug('ImageType.__getattr__ %s', name)

        @_add_doc(name)
        def call_function(*args, **kwargs):
            return pyvips.Operation.call(name, *args, **kwargs)

        return call_function


@_with_metaclass(ImageType)
class Image(pyvips.VipsObject):
    """Wrap a VipsImage object.

    """

    # private static

    @staticmethod
    def _imageize(self, value):
        # careful! self can be None if value is a 2D array
        if isinstance(value, Image):
            return value
        elif _is_2D(value):
            return Image.new_from_array(value)
        else:
            return self.new_from_image(value)

    def __init__(self, pointer):
        # logger.debug('Image.__init__: pointer = %s', pointer)
        super(Image, self).__init__(pointer)

    # constructors

    @staticmethod
    def new_from_file(vips_filename, **kwargs):
        """Load an image from a file.

        This method can load images in any format supported by vips. The
        filename can include load options, for example::

            image = pyvips.Image.new_from_file('fred.jpg[shrink=2]')

        You can also supply options as keyword arguments, for example::

            image = pyvips.Image.new_from_file('fred.jpg', shrink=2)

        The full set of options available depend upon the load operation that
        will be executed. Try something like::

            $ vips jpegload

        at the command-line to see a summary of the available options for the
        JPEG loader.

        Loading is fast: only enough of the image is loaded to be able to fill
        out the header. Pixels will only be decompressed when they are needed.

        Args:
            vips_filename (str): The disc file to load the image from, with
                optional appended arguments.

        All loaders support at least the following options:

        Keyword args:
            memory (bool): If set True, load the image via memory rather than
                via a temporary disc file. See :meth:`.new_temp_file` for
                notes on where temporary files are created. Small images are
                loaded via memory by default, use ``VIPS_DISC_THRESHOLD`` to
                set the definition of small.
            access (Access): Hint the expected access pattern for the image.
            fail (bool): If set True, the loader will fail with an error on
                the first serious error in the file. By default, libvips
                will attempt to read everything it can from a damanged image.

        Returns:
            A new :class:`.Image`.

        Raises:
            :class:`.Error`

        """
        vips_filename = _to_bytes(vips_filename)
        filename = vips_lib.vips_filename_get_filename(vips_filename)
        options = vips_lib.vips_filename_get_options(vips_filename)
        name = vips_lib.vips_foreign_find_load(filename)
        if name == ffi.NULL:
            raise Error('unable to load from file {0}'.format(vips_filename))

        return pyvips.Operation.call(_to_string(ffi.string(name)),
                                     _to_string(ffi.string(filename)),
                                     string_options=_to_string(
                                         ffi.string(options)
                                     ), **kwargs)

    @staticmethod
    def new_from_buffer(data, options, **kwargs):
        """Load a formatted image from memory.

        This behaves exactly as :meth:`new_from_file`, but the image is
        loaded from the memory object rather than from a file. The memory
        object can be a string or buffer.

        Args:
            data (str, buffer): The memory object to load the image from.
            options (str): Load options as a string. Use ``""`` for no options.

        All loaders support at least the following options:

        Keyword args:
            access (Access): Hint the expected access pattern for the image.
            fail (bool): If set True, the loader will fail with an error on the
                first serious error in the image. By default, libvips will
                attempt to read everything it can from a damanged image.

        Returns:
            A new :class:`Image`.

        Raises:
            :class:`.Error`

        """
        name = vips_lib.vips_foreign_find_load_buffer(data, len(data))
        if name == ffi.NULL:
            raise Error('unable to load from buffer')

        return pyvips.Operation.call(_to_string(ffi.string(name)), data,
                                     string_options=options, **kwargs)

    @staticmethod
    def new_from_array(array, scale=1.0, offset=0.0):
        """Create an image from a 1D or 2D array.

        A new one-band image with :class:`BandFormat` ``'double'`` pixels is
        created from the array. These image are useful with the libvips
        convolution operator :meth:`Image.conv`.

        Args:
            array (list[list[float]]): Create the image from these values.
                1D arrays become a single row of pixels.
            scale (float): Default to 1.0. What to divide each pixel by after
                convolution.  Useful for integer convolution masks.
            offset (float): Default to 0.0. What to subtract from each pixel
                after convolution.  Useful for integer convolution masks.

        Returns:
            A new :class:`Image`.

        Raises:
            :class:`.Error`

        """
        if not _is_2D(array):
            array = [array]

        height = len(array)
        width = len(array[0])

        n = width * height
        a = ffi.new('double[]', n)
        for y in range(0, height):
            for x in range(0, width):
                a[x + y * width] = array[y][x]

        vi = vips_lib.vips_image_new_matrix_from_array(width, height, a, n)
        if vi == ffi.NULL:
            raise Error('unable to make image from matrix')
        image = pyvips.Image(vi)

        image.set_type(GValue.gdouble_type, 'scale', scale)
        image.set_type(GValue.gdouble_type, 'offset', offset)

        return image

    @staticmethod
    def new_from_memory(data, width, height, bands, format):
        """Wrap an image around a memory array.

        Wraps an Image around an area of memory containing a C-style array. For
        example, if the ``data`` memory array contains four bytes with the
        values 1, 2, 3, 4, you can make a one-band, 2x2 uchar image from
        it like this::

            image = Image.new_from_memory(data, 2, 2, 1, 'uchar')

        A reference is kept to the data object, so it will not be
        garbage-collected until the returned image is garbage-collected.

        This method is useful for efficiently transferring images from PIL or
        NumPy into libvips.

        See :meth:`.write_to_memory` for the opposite operation.

        Use :meth:`.copy` to set other image attributes.

        Args:
            data (bytes): A memoryview or buffer object.
            width (int): Image width in pixels.
            height (int): Image height in pixels.
            format (BandFormat): Band format.

        Returns:
            A new :class:`Image`.

        Raises:
            :class:`.Error`

        """

        format_value = GValue.to_enum(GValue.format_type, format)
        vi = vips_lib.vips_image_new_from_memory(ffi.from_buffer(data),
                                                 len(data),
                                                 width, height, bands,
                                                 format_value)
        if vi == ffi.NULL:
            raise Error('unable to make image from memory')

        image = pyvips.Image(vi)

        # keep a secret ref to the underlying object
        image._data = data

        return image

    @staticmethod
    def new_temp_file(format):
        """Make a new temporary image.

        Returns an image backed by a temporary file. When written to with
        :func:`Image.write`, a temporary file will be created on disc in the
        specified format. When the image is closed, the file will be deleted
        automatically.

        The file is created in the temporary directory. This is set with
        the environment variable ``TMPDIR``. If this is not set, then on
        Unix systems, vips will default to ``/tmp``. On Windows, vips uses
        ``GetTempPath()`` to find the temporary directory.

        vips uses ``g_mkstemp()`` to make the temporary filename. They
        generally look something like ``"vips-12-EJKJFGH.v"``.

        Args:
            format (str): The format for the temp file, for example
                ``"%s.v"`` for a vips format file. The ``%s`` is
                substituted by the file path.

        Returns:
            A new :class:`Image`.

        Raises:
            :class:`.Error`

        """

        vi = vips_lib.vips_image_new_temp_file(_to_bytes(format))
        if vi == ffi.NULL:
            raise Error('unable to make temp file')

        return pyvips.Image(vi)

    def new_from_image(self, value):
        """Make a new image from an existing one.

        A new image is created which has the same size, format, interpretation
        and resolution as ``self``, but with every pixel set to ``value``.

        Args:
            value (float, list[float]): The value for the pixels. Use a
                single number to make a one-band image; use an array constant
                to make a many-band image.

        Returns:
            A new :class:`Image`.

        Raises:
            :class:`.Error`

        """

        pixel = (Image.black(1, 1) + value).cast(self.format)
        image = pixel.embed(0, 0, self.width, self.height,
                            extend='copy')
        image = image.copy(interpretation=self.interpretation,
                           xres=self.xres,
                           yres=self.yres,
                           xoffset=self.xoffset,
                           yoffset=self.yoffset)

        return image

    def copy_memory(self):
        """Copy an image to memory.

        A large area of memory is allocated, the image is rendered to that
        memory area, and a new image is returned which wraps that large memory
        area.

        Returns:
            A new :class:`Image`.

        Raises:
            :class:`.Error`

        """
        vi = vips_lib.vips_image_copy_memory(self.pointer)
        if vi == ffi.NULL:
            raise Error('unable to copy to memory')

        return pyvips.Image(vi)

    # writers

    def write_to_file(self, vips_filename, **kwargs):
        """Write an image to a file on disc.

        This method can save images in any format supported by vips. The format
        is selected from the filename suffix. The filename can include embedded
        save options, see :func:`Image.new_from_file`.

        For example::

            image.write_to_file('fred.jpg[Q=95]')

        You can also supply options as keyword arguments, for example::

            image.write_to_file('fred.jpg', Q=95)

        The full set of options available depend upon the load operation that
        will be executed. Try something like::

            $ vips jpegsave

        at the command-line to see a summary of the available options for the
        JPEG saver.

        Args:
            vips_filename (str): The disc file to save the image to, with
                optional appended arguments.

        Other arguments depend upon the save operation.

        Returns:
            None

        Raises:
            :class:`.Error`

        """
        vips_filename = _to_bytes(vips_filename)
        filename = vips_lib.vips_filename_get_filename(vips_filename)
        options = vips_lib.vips_filename_get_options(vips_filename)
        name = vips_lib.vips_foreign_find_save(filename)
        if name == ffi.NULL:
            raise Error('unable to write to file {0}'.format(vips_filename))

        return pyvips.Operation.call(_to_string(ffi.string(name)), self,
                                     filename, string_options=_to_string(
                                         ffi.string(options)
                                     ), **kwargs)

    def write_to_buffer(self, format_string, **kwargs):
        """Write an image to memory.

        This method can save images in any format supported by vips. The format
        is selected from the suffix in the format string. This can include
        embedded save options, see :func:`Image.new_from_file`.

        For example::

            data = image.write_to_buffer('.jpg[Q=95]')

        You can also supply options as keyword arguments, for example::

            data = image.write_to_buffer('.jpg', Q=95)

        The full set of options available depend upon the load operation that
        will be executed. Try something like::

            $ vips jpegsave_buffer

        at the command-line to see a summary of the available options for the
        JPEG saver.

        Args:
            format_string (str): The suffix, plus any string-form arguments.

        Other arguments depend upon the save operation.

        Returns:
            A byte string.

        Raises:
            :class:`.Error`

        """
        format_string = _to_bytes(format_string)
        options = vips_lib.vips_filename_get_options(format_string)
        name = vips_lib.vips_foreign_find_save_buffer(format_string)
        if name == ffi.NULL:
            raise Error('unable to write to buffer')

        return pyvips.Operation.call(_to_string(ffi.string(name)), self,
                                     string_options=_to_string(
                                         ffi.string(options)
                                     ), **kwargs)

    def write_to_memory(self):
        """Write the image to a large memory array.

        A large area of memory is allocated, the image is rendered to that
        memory array, and the array is returned as a buffer.

        For example, if you have a 2x2 uchar image containing the bytes 1, 2,
        3, 4, read left-to-right, top-to-bottom, then::

            buf = image.write_to_memory()

        will return a four byte buffer containing the values 1, 2, 3, 4.

        Returns:
            buffer

        Raises:
            :class:`.Error`

        """

        psize = ffi.new('size_t *')
        pointer = vips_lib.vips_image_write_to_memory(self.pointer, psize)
        pointer = ffi.gc(pointer, glib_lib.g_free)

        return ffi.buffer(pointer, psize[0])

    def write(self, other):
        """Write an image to another image.

        This function writes ``self`` to another image. Use something like
        :func:`Image.new_temp_file` to make an image that can be written to.

        Args:
            other (Image): The :class:`Image` to write to,

        Returns:
            None

        Raises:
            :class:`.Error`

        """
        result = vips_lib.vips_image_write(self.pointer, other.pointer)
        if result != 0:
            raise Error('unable to write to image')

    # get/set metadata

    def get_typeof(self, name):
        """Get the GType of an item of metadata.

        Fetch the GType of a piece of metadata, or 0 if the named item does not
        exist. See :class:`GValue`.

        Args:
            name (str): The name of the piece of metadata to get the type of.

        Returns:
            The ``GType``, or 0.

        Raises:
            None

        """

        # on libvips before 8.5, property types must be fetched separately,
        # since built-in enums were reported as ints
        if not at_least_libvips(8, 5):
            gtype = super(Image, self).get_typeof(name)
            if gtype != 0:
                return gtype

        return vips_lib.vips_image_get_typeof(self.pointer, _to_bytes(name))

    def get(self, name):
        """Get an item of metadata.

        Fetches an item of metadata as a Python value. For example::

            orientation = image.get('orientation')

        would fetch the image orientation.

        Args:
            name (str): The name of the piece of metadata to get.

        Returns:
            The metadata item as a Python value.

        Raises:
            :class:`.Error`

        """

        # with old libvips, we must fetch properties (as opposed to
        # metadata) via VipsObject
        if not at_least_libvips(8, 5):
            gtype = super(Image, self).get_typeof(name)
            if gtype != 0:
                return super(Image, self).get(name)

        gv = GValue()
        result = vips_lib.vips_image_get(self.pointer, _to_bytes(name),
                                         gv.pointer)
        if result != 0:
            raise Error('unable to get {0}'.format(name))

        return gv.get()

    def get_fields(self):
        """Get a list of all the metadata fields on an image.

        Returns:
            [string]

        """

        array = vips_lib.vips_image_get_fields(self.pointer)
        names = []
        i = 0
        while array[i] != ffi.NULL:
            name = _to_string(ffi.string(array[i]))
            names.append(name)
            glib_lib.g_free(array[i])
            i += 1
        glib_lib.g_free(array)

        return names

    def set_type(self, gtype, name, value):
        """Set the type and value of an item of metadata.

        Sets the type and value of an item of metadata. Any old item of the
        same name is removed. See :class:`GValue` for types.

        Args:
            gtype (int): The GType of the metadata item to create.
            name (str): The name of the piece of metadata to create.
            value (mixed): The value to set as a Python value. It is
                converted to the ``gtype``, if possible.

        Returns:
            None

        Raises:
            None

        """

        gv = GValue()
        gv.set_type(gtype)
        gv.set(value)
        vips_lib.vips_image_set(self.pointer, _to_bytes(name), gv.pointer)

    def set(self, name, value):
        """Set the value of an item of metadata.

        Sets the value of an item of metadata. The metadata item must already
        exist.

        Args:
            name (str): The name of the piece of metadata to set the value of.
            value (mixed): The value to set as a Python value. It is
                converted to the type of the metadata item, if possible.

        Returns:
            None

        Raises:
            :class:`.Error`

        """
        gtype = self.get_typeof(name)
        if gtype == 0:
            raise Error('metadata item {0} does not exist - '
                        'use set_typeof() to create and set'.format(name))
        self.set_type(gtype, name, value)

    def remove(self, name):
        """Remove an item of metadata.

        The named metadata item is removed.

        Args:
            name (str): The name of the piece of metadata to remove.

        Returns:
            None

        Raises:
            None

        """

        return vips_lib.vips_image_remove(self.pointer, _to_bytes(name)) != 0

    def __repr__(self):
        return ('<pyvips.Image {0}x{1} {2}, {3} bands, {4}>'.
                format(self.width, self.height, self.format, self.bands,
                       self.interpretation))

    def __getattr__(self, name):
        """Divert unknown names to libvips.

        Unknown attributes are first looked up in the image properties as
        accessors, for example::

            width = image.width

        and then in the libvips operation table, where they become method
        calls, for example::

            new_image = image.invert()

        Use :func:`get` to fetch image metadata.

        A ``__getattr__`` on the metatype lets you call static members in the
        same way.

        Args:
            name (str): The name of the piece of metadata to get.

        Returns:
            Mixed.

        Raises:
            :class:`.Error`

        """

        # logger.debug('Image.__getattr__ %s', name)

        # scale and offset have default values
        if name == 'scale':
            if self.get_typeof('scale') != 0:
                return self.get('scale')
            else:
                return 1.0

        if name == 'offset':
            if self.get_typeof('offset') != 0:
                return self.get('offset')
            else:
                return 0.0

        # look up in props first (but not metadata)
        if super(Image, self).get_typeof(name) != 0:
            return super(Image, self).get(name)

        @_add_doc(name)
        def call_function(*args, **kwargs):
            return pyvips.Operation.call(name, self, *args, **kwargs)

        return call_function

    # compatibility methods

    @_deprecated('use Image.get() instead')
    def get_value(self, name):
        return self.get(name)

    @_deprecated('use Image.set() instead')
    def set_value(self, name, value):
        self.set(name, value)

    @_deprecated('use Image.scale instead')
    def get_scale(self):
        return self.scale

    @_deprecated('use Image.offset instead')
    def get_offset(self):
        return self.offset

    # support with in the most trivial way

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        pass

    def __getitem__(self, arg):
        """Overload []

        Use [] to pull out band elements from an image. You can use all the
        usual slicing syntax, for example::

            green = rgb_image[1]

        Will make a new one-band image from band 1 (the middle band). You can
        also write::

            last_two = rgb_image[1:]
            last_band = rgb_image[-1]
            middle_few = multiband[1:-2]

        """

        if isinstance(arg, slice):
            i = 0
            if arg.start is not None:
                i = arg.start

            n = self.bands - i
            if arg.stop is not None:
                if arg.stop < 0:
                    n = self.bands + arg.stop - i
                else:
                    n = arg.stop - i
        elif isinstance(arg, int):
            i = arg
            n = 1
        else:
            raise TypeError

        if i < 0:
            i = self.bands + i

        if i < 0 or i >= self.bands:
            raise IndexError

        return self.extract_band(i, n=n)

    # overload () to mean fetch pixel
    def __call__(self, x, y):
        """Fetch a pixel value.

        Args:
            x (int): The x coordinate to fetch.
            y (int): The y coordinate to fetch.

        Returns:
            Pixel as an array of floating point numbers.

        Raises:
            :class:`.Error`

        """

        return self.getpoint(x, y)

    # operator overloads

    def __add__(self, other):
        if isinstance(other, pyvips.Image):
            return self.add(other)
        else:
            return self.linear(1, other)

    def __radd__(self, other):
        return self.__add__(other)

    def __sub__(self, other):
        if isinstance(other, pyvips.Image):
            return self.subtract(other)
        else:
            return self.linear(1, _smap(lambda x: -1 * x, other))

    def __rsub__(self, other):
        return self.linear(-1, other)

    def __mul__(self, other):
        if isinstance(other, Image):
            return self.multiply(other)
        else:
            return self.linear(other, 0)

    def __rmul__(self, other):
        return self.__mul__(other)

    # a / const has always been a float in vips, so div and truediv are the
    # same
    def __div__(self, other):
        if isinstance(other, pyvips.Image):
            return self.divide(other)
        else:
            return self.linear(_smap(lambda x: 1.0 / x, other), 0)

    def __rdiv__(self, other):
        return (self ** -1) * other

    def __truediv__(self, other):
        return self.__div__(other)

    def __rtruediv__(self, other):
        return self.__rdiv__(other)

    def __floordiv__(self, other):
        if isinstance(other, pyvips.Image):
            return self.divide(other).floor()
        else:
            return self.linear(_smap(lambda x: 1.0 / x, other), 0).floor()

    def __rfloordiv__(self, other):
        return ((self ** -1) * other).floor()

    def __mod__(self, other):
        if isinstance(other, pyvips.Image):
            return self.remainder(other)
        else:
            return self.remainder_const(other)

    def __pow__(self, other):
        return _call_enum(self, other, 'math2', 'pow')

    def __rpow__(self, other):
        return _call_enum(self, other, 'math2', 'wop')

    def __abs__(self):
        return self.abs()

    def __lshift__(self, other):
        return _call_enum(self, other, 'boolean', 'lshift')

    def __rshift__(self, other):
        return _call_enum(self, other, 'boolean', 'rshift')

    def __and__(self, other):
        return _call_enum(self, other, 'boolean', 'and')

    def __rand__(self, other):
        return self.__and__(other)

    def __or__(self, other):
        return _call_enum(self, other, 'boolean', 'or')

    def __ror__(self, other):
        return self.__or__(other)

    def __xor__(self, other):
        return _call_enum(self, other, 'boolean', 'eor')

    def __rxor__(self, other):
        return self.__xor__(other)

    def __neg__(self):
        return -1 * self

    def __pos__(self):
        return self

    def __invert__(self):
        return self ^ -1

    def __gt__(self, other):
        return _call_enum(self, other, 'relational', 'more')

    def __ge__(self, other):
        return _call_enum(self, other, 'relational', 'moreeq')

    def __lt__(self, other):
        return _call_enum(self, other, 'relational', 'less')

    def __le__(self, other):
        return _call_enum(self, other, 'relational', 'lesseq')

    def __eq__(self, other):
        # _eq version allows comparison to None
        if other is None:
            return False

        return _call_enum(self, other, 'relational', 'equal')

    def __ne__(self, other):
        # _eq version allows comparison to None
        if other is None:
            return True

        return _call_enum(self, other, 'relational', 'noteq')

    def floor(self):
        """Return the largest integral value not greater than the argument."""
        return self.round('floor')

    def ceil(self):
        """Return the smallest integral value not less than the argument."""
        return self.round('ceil')

    def rint(self):
        """Return the nearest integral value."""
        return self.round('rint')

    def bandand(self):
        """AND image bands together."""
        return self.bandbool('and')

    def bandor(self):
        """OR image bands together."""
        return self.bandbool('or')

    def bandeor(self):
        """EOR image bands together."""
        return self.bandbool('eor')

    def bandsplit(self):
        """Split an n-band image into n separate images."""
        return [x for x in self]

    def bandjoin(self, other):
        """Append a set of images or constants bandwise."""
        if not isinstance(other, list):
            other = [other]

        # if [other] is all numbers, we can use bandjoin_const
        non_number = next((x for x in other
                           if not isinstance(x, numbers.Number)),
                          None)

        if non_number is None:
            return self.bandjoin_const(other)
        else:
            return pyvips.Operation.call('bandjoin', [self] + other)

    def composite(self, other, mode, **kwargs):
        """Composite a set of images with a set of modes."""
        if not isinstance(other, list):
            other = [other]
        if not isinstance(mode, list):
            mode = [mode]

        # modes are VipsBlendMode enums, but we have to pass as array of int --
        # we need to map str->int by hand
        mode = [GValue.to_enum(GValue.blend_mode_type, x) for x in mode]

        return pyvips.Operation.call('composite', [self] + other, mode, **kwargs)

    def bandrank(self, other, **kwargs):
        """Band-wise rank filter a set of images."""
        if not isinstance(other, list):
            other = [other]

        return pyvips.Operation.call('bandrank', [self] + other, **kwargs)

    def maxpos(self):
        """Return the coordinates of the image maximum."""
        v, opts = self.max(x=True, y=True)
        x = opts['x']
        y = opts['y']
        return v, x, y

    def minpos(self):
        """Return the coordinates of the image minimum."""
        v, opts = self.min(x=True, y=True)
        x = opts['x']
        y = opts['y']
        return v, x, y

    def real(self):
        """Return the real part of a complex image."""
        return self.complexget('real')

    def imag(self):
        """Return the imaginary part of a complex image."""
        return self.complexget('imag')

    def polar(self):
        """Return an image converted to polar coordinates."""
        return _run_cmplx(lambda x: x.complex('polar'), self)

    def rect(self):
        """Return an image converted to rectangular coordinates."""
        return _run_cmplx(lambda x: x.complex('rect'), self)

    def conj(self):
        """Return the complex conjugate of an image."""
        return self.complex('conj')

    def sin(self):
        """Return the sine of an image in degrees."""
        return self.math('sin')

    def cos(self):
        """Return the cosine of an image in degrees."""
        return self.math('cos')

    def tan(self):
        """Return the tangent of an image in degrees."""
        return self.math('tan')

    def asin(self):
        """Return the inverse sine of an image in degrees."""
        return self.math('asin')

    def acos(self):
        """Return the inverse cosine of an image in degrees."""
        return self.math('acos')

    def atan(self):
        """Return the inverse tangent of an image in degrees."""
        return self.math('atan')

    def log(self):
        """Return the natural log of an image."""
        return self.math('log')

    def log10(self):
        """Return the log base 10 of an image."""
        return self.math('log10')

    def exp(self):
        """Return e ** pixel."""
        return self.math('exp')

    def exp10(self):
        """Return 10 ** pixel."""
        return self.math('exp10')

    def erode(self, mask):
        """Erode with a structuring element."""
        return self.morph(mask, 'erode')

    def dilate(self, mask):
        """Dilate with a structuring element."""
        return self.morph(mask, 'dilate')

    def median(self, size):
        """size x size median filter."""
        return self.rank(size, size, (size * size) / 2)

    def fliphor(self):
        """Flip horizontally."""
        return self.flip('horizontal')

    def flipver(self):
        """Flip vertically."""
        return self.flip('vertical')

    def rot90(self):
        """Rotate 90 degrees clockwise."""
        return self.rot('d90')

    def rot180(self):
        """Rotate 180 degrees."""
        return self.rot('d180')

    def rot270(self):
        """Rotate 270 degrees clockwise."""
        return self.rot('d270')

    # we need different _imageize rules for this operator ... we need to
    # _imageize th and el to match each other first
    @_add_doc('ifthenelse')
    def ifthenelse(self, th, el, **kwargs):
        for match_image in [th, el, self]:
            if isinstance(match_image, pyvips.Image):
                break

        if not isinstance(th, pyvips.Image):
            th = Image._imageize(match_image, th)
        if not isinstance(el, pyvips.Image):
            el = Image._imageize(match_image, el)

        return pyvips.Operation.call('ifthenelse', self, th, el, **kwargs)

    def scaleimage(self, **kwargs):
        """Scale an image to 0 - 255.

        This is the libvips ``scale`` operation, renamed to avoid a clash with
        the ``scale`` for convolution masks.

        Keyword args:
            exp (float): Exponent for log scale.
            log (bool): Switch to turn on log scaling.

        Returns:
            A new :class:`Image`.

        Raises:
            :class:`.Error`

        """

        return pyvips.Operation.call('scale', self, **kwargs)


__all__ = ['Image']
